Sprayer and other hand-operated pump type dispensers, as well as squeeze bottle dispensers, are well known in the art but all are involved with the problem of replenishing the air within the container as the contents are expelled so as to restore normal atmospheric pressure and also to prevent inward collapse of the container because of low internal pressure. Various ways of solving this problem have been presented in the past but they fall short of accomplishing this purpose by allowing leakage of the contents through the vent means which is undesirable for many reasons including the safety of the user where the contents may be toxic or injurious to the skin. Even leakage of a fluid such as water is undesirable since it could damage furniture or clothing. Attempts to solve this problem also tend to present devices which become complex, difficult to make and expensive. Also, they may require an additional operation by the user to open or close the vent which not only represents a nuisance to the user but can easily be forgotten with a resultant spill. Applicant, however, solves these problems by providing a completely automatic one-way vent seal which can be expected to seal effectively without attention by the user of the device and yet will open upon demand of a lowered pressure within the container. It is also simple, easy to make and should be relatively inexpensive to manufacture.
An important feature of the present invention is the control of the extent of the maximum vent valve opening which is established in the manufacture of the assembly of cap and body. The maximum opening thereafter remains the same and is completely independent of the degree of tightening which a user may apply to the cap unless, of course, the cap becomes actually distorted due to excessive over tightening which is an unlikely occurrence with the usual hand tightening.
In the art, several patents show various arrangements designed to achieve the venting of the container's interior. For instance, U.S. Pat. No. 3,685,739 to Vance R. Vanier includes a typical sprayer attached to a container for liquids by means of a screw cap which clamps the sprayer to the container with a gasket or sealing washer therebetween. This gasket extends in a frusto-conical form downwardly therefrom with its lower edge touching the stem of the body inside the neck of the container and providing a seal. An air passage allows access of air into the interior of the cone and this air exerts itself upon the seal, and, when the air pressure inside the container becomes less than the outside air, the seal deflects away from the stem of the body and allows air to enter the container. The present invention, however, differs from this showing in several ways including the fact that applicant's seal is unitary with the cap and does not represent a separate part which may become separated from the cap and lost. Also, the seal provided in the present invention makes it unnecessary to use rubber which may be incompatible with the particular liquid in the container and cause the rubber to swell, rot or otherwise lose its shape and resiliency and thus cause it to lose its ability to seal and vent properly. The location of the seal of the present invention outside of the neck of the container also alleviates this problem because of the remoteness of the seal from the liquid in the container.
Another U.S. Pat. No. 3,780,951 to Richard T. Powers includes a dispenser held to a container by a screw cap with a gasket between the body of the dispenser and the rim of the container. The vent here includes a collar on the dispenser body which is screwed down by the operator to close a vent passage and is unscrewed to open it. It is not automatic in action as is the vent device of the dispenser in the present invention and is manually operated.
Another U.S. Pat. No. 3,587,940 to Roy T. Ellis shows a frusto-conical seal member generally similar to that of the Vanier patent mentioned above, except that sealing occurs nearer the base of the frusto-cone. This arrangement also has the inherent disadvantages of the Vanier showing as is also the case with respect to French Pat. No. 1,577,522/1969 to Rene' Fedit et al.
Another U.S. Pat. No. 3,897,006 to Tetsuya Tada shows a vent valve which is inside of the dispenser body and is part of an inner sleeve and not part of the cap itself. In addition, the valve is mechanically operated by manual manipulation of the pump mechanism to push the valve seal off its seat by means of a slender rod.
Another U.S. Pat. No. 3,927,834 to Tetsuya Tada shows a vent passage in the dispenser body plugged by a trigger catch which unblocks the passage when the catch is removed from the trigger. Similarly, in the U.S. Pat. No. 3,726,442 to Thomas N. Davidson et al, a stem attached to the hinged upper part of the sprayer body blocks and unblocks a vent passage as the sprayer is operated through its operating cycle.
Another U.S. Pat. No. 3,749,290 to Lewis A. Micallef shows a trigger sprayer wherein the trigger is arranged to squeeze a pumping member which moves away from the body to open a vent passage. Also, the U.S. Pat. No. 3,986,644 to Richard P. Grogan shows a trigger-operated dispenser which squeezes its pumping member and moves it away from the dispenser body to open a vent passage.
None of the above-mentioned patents show the vent seal member as part of the cap itself nor do they show the novel combination of the present invention including the controlled maximum vent opening.